Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physics > Forces and Motion > Flashcards

Forces and Motion Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

Why so the distance between different planets’ orbits not constant?

A

1) different speeds
2) different orbits
3) variable relative motion (both on same side of sun then on opposite sides)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why are the forces balanced on an object travelling at a constant velocity?

A

1) acceleration needs an unbalanced force
2) constant velocity means no acceleration
3) absence of unbalanced force (no resultant force)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is meant by the phrase energy is conserved?

A

Total energy always the same (energy cannot be created or destroyed)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Explain how a falling object can reach terminal velocity

A

1) object has weight
2) so it accelerates downwards
3) there is a force of drag upwards, opposing the movement
4) drag increases as speed increases
5) eventually drag is equal to weight
6) hence resultant force is zero
7) hence object travels at a constant speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

State a difference between the orbit of a moon and the orbit of a planet

A

moon orbits a planet and planet orbits a star

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why would a ball (hit with the same force) travel further on the moon than it would do on earth?

A

1) value of g lower on the moon
2) lack of air resistance on the moon
3) time of flight greater

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is meant by the term elastic behaviour?

A

Returns to original shape when the force causing deformation is removed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why do planets closer to the sun take less time to orbit it?

A

1) smaller orbital path for closer planets

2) larger speed for closer planets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What effect does a cushion of air have on a moving object?

A

1) speed does not reduce much
2) because friction reduced
3) because cushion of air lifts the object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is Hooke’s law?

A

Before the elastic limit is reached the force is directly proportional the extension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is Newton’s second law?

A

F=ma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

When measuring the extension of a spring how can you measure it more accurately?

A

1) no zero error
2) ruler should be vertical
3) use a ruler with finer calibrations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Explain in terms of forces what is meant by terminal velocity

A

1) forces on the object are equal so no resultant force
2) stops accelerating
3) velocity is constant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How do the orbits of earth and mars differ?

A

Different orbital radii

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are scalar quantities?

A

Quantities which can be completely described by their size alone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are vector quantities?

A

Quantities for which direction is important as well as their size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is a force?

A

A push or pull of one body on another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe the graph for the extension of a helical spring as force increases

A

1) initially force and extension are directly proportional
2) once elastic limit is reached the spring stops stretching uniformly
3) once elastic limit is passed spring has permanent stretch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe the graph for the extension of a cooper wire as force increases

A

1) initially extension and force are directly proportional
2) then wire begins to yield
3) the wire exhibits plastic flow as the extension becomes much larger for a given increase in force
4) eventually wire breaks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Describe the graph for the extension of a rubber band as force increases

A

1) easy to stretch at first
2) then more difficult
3) at no stage is the extension of the rubber band proportional to the force applied

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What makes up the overall stopping distance?

A

Thinking distance + breaking distance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What affects thinking distance (reaction time)?

A

Age, use of mobile phones and alcohol consumption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What affects breaking distance?

A

1) speed
2) braking force (if brakes are worn if road surface is slippery)
3) mass of car

24
Q

What is the relationship between braking distance and speed?

A

Speed square did proportional to the breaking distance (twice speed = four times braking distance)

25
Q

What is the center of gravity of an object?

A

The point from which all of the weight of the object may be thought to act

26
Q

How do you find the centre of mass of an irregular object?

A

Using pivot and drawing vertical lines to ground. Cross over = centre of mass

27
Q

What makes an object more stable?

A

1) low center of gravity

2) base as wide as possible

28
Q

What does gravitational force cause?

A

1) planets to orbit the sun
2) the moon and artificial satellites to orbit earth
3) comets to orbit the sun

29
Q

What does the strength of the gravitational force between two objects depend on?

A

1) their masses

2) their distance apart

30
Q

Is length a vector or scalar quantity?

A

Scalar

31
Q

Is displacement a vector or scalar quantity?

A

Vector

32
Q

Is time a vector or scalar quantity?

A

Scalar

33
Q

Is temperature a vector or scalar quantity?

A

Scalar

34
Q

Is velocity a vector or scalar quantity?

A

Vector

35
Q

Is momentum a vector or scalar quantity?

A

Vector

36
Q

Is potential difference a vector or scalar quantity?

A

Scalar

37
Q

Is acceleration a vector or scalar quantity?

A

Vector

38
Q

Is pressure a vector or scalar quantity?

A

Scalar

39
Q

Is force a vector or scalar quantity?

A

Vector

40
Q

Is weight a vector or scalar quantity?

A

Vector

41
Q

Why is force a vector?

A

Because when two or more forces act on an object then their directions must be taken into account when calculating the resultant force so direction as well as size is important

42
Q

How do you calculate resultant force?

A

Add forces acting in the same direction together or subtract forces acting in opposite directions

43
Q

What happens to momentum when two objects collide?

A

The change in momentum will be equal and opposite for both objects (if one loses momentum then the other will gain an equal amount) as momentum is conserved

44
Q

use ideas about momentum to explain how seat belts can reduce injuries to passengers during a crash

A

1) Same momentum change with or without a seatbelt
2) but time of impact increases
3) which reduces the rate of momentum change
4) therefore reducing the average force

45
Q

Why do you bend your legs when you land after a jump?

A

Increase the stopping time and hence reduce the force

46
Q

Why are cars built with crumple zones?

A

Car crumpled as it hits something increasing the stopping time and hence the force will be smaller

47
Q

Why are cars fitted with air bags?

A

Bags cushion the impact allowing your momentum to reach zero more slowly so the force involved is smaller

48
Q

What is Newton’s third law?

A

When one object exerts a force on a second object, the second object exerts a force of the same size and type (but in the opposite direction) on the first object
AKA: action and reaction are equal and opposite

49
Q

What is the principle of moments?

A

The sum of the anti-clockwise moments = the sum of the clockwise moments
AKA: force x perpendicular distance on one side = force x perpendicular distance on the other side

50
Q

What happens to a boy on a skateboard when he throws a ball?

A

1) boy and skateboard move backward (in the opposite direction to the ball)
2) because of the conservation of momentum
3) momentum of ball and boy are equal and opposite
4) because momentum initially zero

51
Q

how can you reduce the friction between two surfaces?

A

1) place a lubricant between the two surfaces
2) make the surfaces smoother
3) decrease weights/masses on block

52
Q

what is the conservation of momentum?

A

momentum after = momentum before

53
Q

explain how wearing knee pads protects your knees if you fall

A

1) increased time of impact
2) same change in momentum
3) force is rate of change in momentum
4) reduces force on knee

54
Q

is distance a vector or scalar quantity?

A

scalar

55
Q

explain why a full-body harness is used in a racing car, instead of an ordinary seatbelt

A

1) there is a larger force during impact
2) straps have a greater area over which force acts
3) larger area of straps reduces the pressure

Physics (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions